At the mention of Google, marketer's eyes brighten, and it's no wonder.

It's not just that Google spreads across the internet like a giant octopus. It's what the mega search engine delivers in sales of every conceivable product from dishwashers to diapers to 200-year-old antique clocks. It is the great marketing machine of these times.

There's just one flaw in that perception. It's a huge one.

Google may be the point of transaction, the last step before the consumer completes an online purchase, but in fact that purchase was preceded by perhaps dozens of ad messages, perhaps hundreds, that served to persuade the consumer to make that decision.

Google gets the credit for the sale. Google profits handsomely from the paid search ads that appeared on the page with the link that led to the purchase.

But the web sites that served those ads that led up to the sale are entirely left out. They get little if any credit for the sale and none of the revenue from that last click.

It's not an equitable system. Indeed, debate now rages in media circles as to how to improve the system so that all parties that played a role in that purchase are recognized and rewarded for their contribution.

Some are arguing for a system that creates a history of ad impressions leading up to a purchase and then rewards each contributor with a share of revenue Google now receives for that last click.

While it would indeed be fairer, such a shared payment system would be highly impractical to set up. We'll colonize Mars first.

Atlas and DoubleClick have taken steps to better track impressions leading up to transactions, and these are good starts, but far more work needs to be done. It's going to take the support of the internet's major players to fund the research needed to come up with the technology that will enable tracking and proper credit to all players up through the transaction process.

That effort ought to be led by such industry groups as the Interactive Advertising Bureau, and it ought to begin now.

Think of the benefits with such a system in place. Marketers would learn which ads really worked in driving sales, as well as when and where. Greater accountability has always been the promise of the internet.

This would deliver on that promise.And of course, it would make the internet all that more attractive to that many more marketers.

Media agencies would win by being able to better plan and buy for their clients.

It would lead to a more equitable distribution of rewards by advertisers up the media food chain, without the necessity of a shared payment structure.

Web sites that were found to have delivered ads that led to sales would be able to charge higher CPMs, taking a greater share of that total ad dollar. They would be rewarded, as they should be, for doing a better job of delivering the right ad message to the right reader in the right environment.

Google and other search engines would see their share diminish, though they would still be rewarded for that last click.

Also, and no less important, the system would work to the disadvantage of that growing sea of sites cluttering the internet space that bring no real value to advertisers.